Weight sensing attachment for cable anchors



Jan. 25, 1955 E.-L. DECKER WEIGHT SENSING ATTACHMENT FOR CABLE ANCHORSFiled. NOV. 27, 1950 VII/[Ill WI I IIIIIIIII INVENTOR. -Z/.MEQ L-DECKEQ,

47' TOENE Y- WEIGHT SENSING ATTACHMENT FOR CABLE AN CHORS Elmer L.Decker, Long Beach, Calif., assignor to Martin- Decker Corporation, LongBeach, Calif., a corporation of Delaware Application November 27, 1950,Serial No. 197,699

14 Claims. (Cl. 73-143) This invention relates in general to apparatusfor indicating the load or weight on the lines of cable hoist systemsemployed in connection with rotary well drilllng rigs, and in particularto the conversion of cable anchoring devices for such lines to combinedweight indlcatmg and cable anchoring units.

Cable anchors of the type to which this invention re- 'lates have goneinto extensive use and comprise a body member adapted to be fixed to astationary support, a snubbing drum mounted for limited turning movementon the body member and adapted to receive a plurality of windings of thecable, and a releasable clamp fixed on the body member apart from thedrum for dead-ending the cable after the cable has been wound around thedrum. The drum relieves the strain on the clamp and the clamp permits offeeding fresh cable into the system as requlred without dismantling theanchoring device.

It is the primary object of this invention to provide a weight sensingadapter unit for converting a cable anchor of the character described toa combined cable anchoring and weight indicating apparatus withoutnecessitating any change in the construction of the cable anchor.

It is another object of this. invention to provide a simply constructedand inexpensive adapter unit such as described, which may be readilyinterposed between a stationary supporting structure and a cable anchorofthe type described, as a mounting therefor and to convert the anchorfor use as a weight indicator when connected with a suitable indicator,the resultant converted unit having all of the advantages of its cableanchoring component plus the advantage of accurate indication of theweight on the cable anchored thereto.

This invention possesses many other advantages and has other objectswhich may be made more easily apparent from a consideration of oneembodiment of the invention. For this purpose there is shown a form inthe ited, States Pa m drawings accompanying and forming part of thepresent specification. This form will now be described in detail,illustrating the general principles of the, invention; but it is to beunderstood that this detailed description is not to be taken in alimiting sense, since the scope of the invention is best defined by theappended claims.

Referring to the drawings:

Fig. 1 is a fragmentary side elevational view partly in section of aweight sensing unit constructed in accordance with this invention;

Fig. 2 is an end elevation of the unit looking in the direction of thearrow 2 in Fig. 1;

Fig. 3 is an end elevation of the unit partly in section looking in thedirection of the arrow 3 of Fig. 1;

Fig. 4 is an enlarged fragmentary side elevation partly in section ofthe sensing unit of this invention as it would appear when in use as amounting for a cable anchor and as connected with a weight indicator;

Fig. 5 is an enlarged sectional view taken substantially on the line 5-5of Fig. 4; and

Fig. 6 is a fragmentary front elevational view of the apparatus shown inFig. 4.

The present invention as shown in the accompanying drawing comprises aweight sensing unit A for converting a cable anchor B of the type shownin Fig. 4, to a combined cable anchor and weight indicator, the cable Cbeing for example, the dead line of a hoist system for a rotary welldrilling rig.

The sensingunit A hereof is designed for use in connection'with a cableanchor of the type which includes an upstanding body member 7 having abase portion 8 ice at its lower end provided with openings 9 wherebynormally the base portion would be secured to a stationary support suchas the structure D here shown and which may be a part of or secured onthe well derrick structure or drill platform of a well. At its upper endthe body member 7 supports for rotation on an axle 10, a snubbing drum11 adapted to have a plurality of loops of the cable C wound thereon.

The cable C is dead-ended on the body member 7 by means of a releasablecable clamp 12 located below the axis of the drum 11 and to one side ofthe drum. The cable extends past the clamp to a reel or spool of cablenot shown, whereby fresh cable may be introduced into the system asrequired without dismantling the cable anchor, it only being necessaryto loosen the clamp and extend fresh cable into the system through thedevice.

Essentially the weight sensing adapter A of this invention comprises atiltable mounting member for the cable anchor unit B, means for tiltablysecuring the mounting member on the support D, and a sensing elementwhich respond-s to bodily movement of anchor unit and mounting memberincident to loads imposed on the cable and includes means foroperatively connecting the sensing element with an indicator. As hereprovided the sensing adapter includes a substantially rectangularplate-like mounting member 14 pivotally or hingedly connected at one endto one end of a similar plate-like base member 15 so as to overlie thelatter member.

A hydraulic sensing element 16 is mounted between the members 14 and 15and connected with the other ends thereof so as to respond to tiltingmovement of the mounting member 14. Means in the form of a fitting 17 isprovided on the sensing element 16 whereby an operative connection maybe made, as by means of a fluid line 18, with a weight indicator 19. Theindicator may be located at any suitable point in sight of the operatorsof the drilling rig. Y

Movement limiting means 20 is provided between the members 14 and 15 tolimit the tilting movement of the member 14 within safe limitsinconsideration of the limited movement of the sensing element, to preventdamage of the latter.

The mounting member 14 is provided with openings 21 adapted to registerwith the openings 9 in the base portion 8 of the anchor unit B whereby aU-bolt 22 and nuts 23 may be employed as shown in Figures 4 and 5 torigidly secure the base portion 8 to the member 14 with the loop portion22 of the bolt depending below the plate as a part of themovement-limiting means 20. -A similar U-bolt 24 is secured by nuts 25on the stationary support 1), extends through the member 15, and has itsloop portion 24 to complete the means 20, for limiting the tilting ofthe member 14.

At one end, the member 14 is provided with opposed depending andapertured ears 26 which embrace an upstanding car 27 on the base member15, the ear 27 havlng an enlarged transversely apertured head portion27, the aperture through which registers with the apertures 111 the ears26 to accommodate a pivot pin 28 held in place by cotter pins 29.Suitable anti-friction bearings 30 and 31 are seated in the ears 26 andopposite ends of the head 27 respectively, as shown in Fig. 3.

The base member 15 is secured to the support structure D by means ofbo1ts 32 and nuts 33, the U-bolts 24 and nuts 25 also serving to securethe base member to the support as will be seen with reference to Figs. 4and 5.

The sensing element 16, as best shown in Fig. 1, includes a cylinder 34having an integral end wall 35, and a removable end wall 36. A piston 37is operable in the cylinder between the end walls thereof, against abody of fluid above the piston. A filling opening 38 in the cylinder,closed by a removable plug 39, provides for charging the cylinder andassociated hydraulic system with desired amounts of fluid to regulatethe weight indicating action best to suit the conditions at hand. i

The removable wall 36 of the cylinder 34 has a vent port 36' to prevententrapped air or fluid from interfering with the movement of the piston37. This wall is coupled to the base member 15 by means of a pair ofdepending ears 40 thereon, a pivot block 41, ears 42 on the base member15 and pivot pins 43 and 44 respectively pivotally connecting the endsof the block with said ears. These pivot pins are normal one to theother whereby a universal joint is provided between the lower end of thecylinder 34 and the base member 15. In this connection, it will be seenwith reference to Figs. 1 and 2 that the base member is provided with aslot 45 between the cars 42 permitting free movement of the lower end ofthe block 41.

The piston 37 has a piston rod 46 which is slidable through the end wall35 of the cylinder 34 and is threadedly connected as at 47 with yoke 48.Pivoted on a pin 49 between ears 50 on the yoke, is a pivot block 51corresponding to the block 41. The upper end of the block 51 is pivotedby means of a pin 52 to cars 53 depending from the mounting member 14,there being a slot 54 in the member 14 to accommodate the block 51. Thepins 49 and 52 are arranged at right angles to one another, therebyproviding a universal joint between the upper end of the sensing element16 and the mounting member 14-. In mounting the element 16 with twouniversal joints as here provided, no critical machining is required asto the mounting means and these joints compensate for any misalignmentofthe parts and prevent damage of the sensing element which mightotherwise take place due to angular rbriovlenent of the member 14relative to the base mem- The anchor unit B mounted as here provided onthe unit A, will move bodily on the mounting member 14 responsive tovariations in the load or pull on the cable C and as a result of thismovement, the member 14 will cause the piston 37 to move and transmitthrough the fluid contained in the cylinder, the line 18 and theindicator 19, forces for actuating the indicator to show the load orweight on the cable. The drum will relieve the strains on the cableclamp. The clamp when loosened makes it possible readily to extend freshcable into the system without disturbing or in any manner adjusting thecombined anchor and indicator other than loosening of the clamp.

It is important to note that the opposed mounting members 14 and 15 areconnected for relative movement about an axis which is below the axis ofthe snubbing drum 11 of the cable anchor mounted on the cable anchorsupporting surface of the plate 14, and that the plate 15 is providedwith a mounting surface adapted to be secured to the supportingstructure D. Thus, the weight sensing attachment as here providedconstitutes a simple, compact and inexpensive unit subject to readyapplication to a cable anchor of the type here shown for converting thecable anchor to a combined weight indicator and cable anchor having allof the efficiency of the cable anchor as heretofore used, plus provisionfor an accurate indication of the weight on the cable anchored thereto.

1 claim:

1. In a weight sensing unit for attachment to a cable anchor, a pair ofopposed members, means connecting said members for relative pivotalmovement, means between and connected with said members for limitingrelative movement thereof, one of said opposed members being adapted tobe fixed to a stationary support, means on the other of said membersproviding a seat for the body member of said cable anchor, said othermember having means providing for the fixation of said body member tosaid seat so as to prevent relative movement between said seat and saidbody member, a hydraulic sensing element connected with said opposedmembers for operation responsive to relative movement between saidopposed members, and means on the sensing element for fixing aconnection thereof with an indicator.

2 In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit for a loadsustaining cable, wherein said anchoring device is provided with a baseadapted to be immovably fixed to a support, a pair of opposed members,means connecting said members for relative pivotal movement, meansbetween and connected with said members for limiting relative movementthereof, said members being adapted to be mounted between the base ofsaid cable anchoring device and a stationary support, with one of saidmembers fixed to the stationary support and the other member mmovablyfixed tothe base of the cable anchoring device, and a load sensingelement mounted between and fixedly connected with said opposed membersfor operation responsive to movement of the opposed mem' bers on whichsaid cable anchoring device is mounted.

3. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit for a loadsustaining cable wherein said device is provided with a base, a pair ofopposed and hingedly connected members adapted to be mounted between thecable anchoring device and a stationary support with one of said membersfixed to the stationary support and the other member immovably fixed tothe base of the cable anchoring device, a sensing element, means forminguniversal joints connecting said element with said opposed members, saidsensing element operating responsive to relative movement between saidmem bers in a direction away from one another, means on said element foroperatively connecting said element with an indicator, and means locatedbetween the hinged connection of said members and said sensing elementfor limiting relative movement between said opposed members.

4. In combination, a snubbing drum, a body member on which said drum ismounted for limited rotary movement, a cable clamp fixed on said bodymember for deadending a load-sustaining cable after the winding of thecable around the drum, a tiltable mounting member, means fixing saidbody member to said mounting member for movement therewith and againstmovement relative thereto, means for tiltably mounting said mountingmember on a stationary support, a load sensing element mounted betweensaid support and said tiltable member for operation responsive to thetilting of said tiltable member and body member as a unit, and means onsaid sensing element for operatively connecting the sensing element withan indicator.

5. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit for a loadsustaining cable, a pair of opposed members, means connecting saidmembers for relative movement, said members being adapted to be mountedbetween the cable anchoring device and a stationary support, with one ofsaid members fixed to the stationary support and the other member fixedto the cable anchoring device, a load sensing element mounted betweenand connected with said opposed members for operation responsive tomovement of said other member, means on the sensing element forconnecting the sensing element with an indicator, and cooperative stopmembers fixed to and between said opposed members forlimiting relativemovement of said members, one of said stop members being operable forsecuring said other of said opposed members to said cable anchoringdevice.

6. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit, a pair of opposedmembers, means connecting said members for relative pivotal movement,said members having openings therein providing for the fastening of onemember to a stationary support and providing for the fastening of theanchoring device upon the other member, said other member having theuppermost surface thereof formed as a seat for said anchoring device, ahydraulic sensing unit comprising a piston connected to one of saidmembers and a cylinder connected with the other of said members, meansconnected with said members between said first named means and saidsensing unit for limiting relative movement between said members, andmeans on said cylinder for effecting an operative connection thereofwith an indicator.

7. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit, a pair of opposedmembers, means connecting said members for relative movement, saidmembers having openings therein providing for the fastening of onemember to a stationary support and providing for the fastening of theanchoring device upon the other member, means connected with saidmembers for limiting relative movement thereof, a hydraulic sensing unitcomprising a piston, means forming a universal joint connecting saidpiston with one of said members, a cylinder in which the piston isoperable, means forming a universal joint connecting the cylinder withthe other of said members, and means on the cylinder for effecting anoperative connection of the sensing element with an indicator.

8. In a weight sensing unit for attachment to a cable anchor, the cableanchor comprising a snubbing drum mounted for turning on a body memberand adapted to receive a plurality of windings of a cable, and a cableclamp on said body member for dead-ending the cable after the windingthereof around the drum; said sensing unit including a pair of opposedmembers, means connecting said members for relative pivotal movement,one of said opposed members being adapted to be fixed to a stationarysupport, the other of said members being adapted to serve as a seat forthe body member of said cable anchor and having means providing for thefixation thereof to said body member for movement therewith, a:hydraulic sensing element disposed between and connected with saidopposed members for operation responsive to relative movement betweensaid opposed members, means on the sensing element for effecting anoperative connection thereof with an indicator, and interconnected stopmembers connected with said opposed members between said first namedmeans and said sensing unit for limiting relative movement of saidopposed members.

9. In combination, a snubbing drum, a body member on which said drum ismounted for limited rotary movement, a cable clamp fixed on said bodymember for deadending a load-sustaining cable at a point to one side ofsaid drum, a tiltable mounting member, means fixing said body member tosaid mounting member for movement therewith and against movementrelative thereto, means for tiltably mounting said mounting member on astationary support, a load sensing element connected with said tiltablemember for operation responsive to the tilting thereof and the bodymember as a unit, means on said sensing element for operativelyconnecting the sensing element with an indicator, and means cooperablewith the means for fixing said body member to said mounting member forlimiting tilting movement of said mounting member.

10. In a weight sensing unit for attachment to a cable anchor, the cableanchor comprising a snubbing drum mounted for turning on a body memberand adapted to receive a plurality of windings of a cable, and a cableclamp on said body member for dead-ending the cable after the windingthereof around the drum; said sensing unit including a pair of opposedmembers, means connecting said members for relative movement about anaxis below the axis of said drum, one of said opposed members having asurface adapted to be fixed to a stationary support, means providing onthe uppermost part of the other of said members a surface adapted to besecured to the body member of said cable anchor, a hydraulic sensingelement connected with said opposed members for operation responsive torelative movement between said opposed members, means on the sensingelement for effecting an operative connection thereof with an indicator,interconnected elements connected with said members for limitingrelative movement thereof, and means including one of said elements forfixing said body member to said other member.

11. In combination, a snubbing drum, a body member on which said drum ismounted for rotary movement, a cable clamp fixed on said body member fordead-ending a load-sustaining cable at a point to one side of said drum,a tiltable mounting member, means fixing said body member to saidmounting member for movement therewith and against movement relativethereto, means mounting said mounting member for movement about an axisbeneath said body member, a load sensing element pivotally connectedwith said tiltable member and said last named means, and means on saidsensing element for operatively connecting the sensing element with anindicator.

12. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit for a loadsustaining cable, a pair of opposed members, one of which has a surfaceadapted to mount the cable anchor, means connecting said members forrelative pivotal movement about an axis beneath said cable anchor, meansbetween and connected with said members for limiting relative movementthereof, the other of said members being adapted to be fixed to astationary support, and a hydraulic load sensing element pivotallyconnected with said opposed members for operation responsive to movementof the opposed member on which said cable anchoring device is mounted,said connecting means and said element being respectively locatedadjacent the ends of said members, and means on the sensing element forconnecting the sensing element with an indicator.

13. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit for a loadsustaining cable, a pair of opposed members, said members being adaptedto be mounted between the cable anchoring device and a stationarysupport, with one of said members having a surface fixed to thestationary support and the other member having a surface fixed to thecable anchoring device, means pivotally connecting said members betweensaid surfaces; means between and connected with said members forlimiting relative movement thereof, a load sensing element mountedbetween and pivotally connected with corresponding ends of said opposedmembers for operation responsive to movement of the member on which saidcable anchoring device is mounted, means on the sensing element forconnecting the sensing element with an indicator, and means for limitingrelative movement of said members.

14. In a sensing unit for converting a cable anchoring device to acombined weight indicating and cable anchoring unit, a pair of opposedmembers, said members having openings therein providing for thefastening of one member to a stationary support and for the fastening ofthe anchoring device upon the other member, means connecting said othermember with said one member for move ment upwardly therefrom about anaxis below said cable anchor; means for limiting such movement of saidother member, a hydraulic sensing unit comprising a piston, meansforming a universal joint connecting said piston with said other member,a cylinderin which the piston is operable, means forming a universaljoint connecting said cylinder with said one member, and means on thecylinder for efiecting an operative connection of the sensing elementwith an indicator.

References Cited in the file of this patent UNITED STATES PATENTS680,371 Brittan Aug. 13, 1901 1,692,057 Smith Nov. 20, 1928 1,934,201Miller Nov. 7, 1933 2,025,928 Wunsch Dec. 31, 1935 2,235,279- BunkerMar. 18, 1941 2,282,685 Timbs May 12, 1942 2,349,228 Wolff May 16, 19442,488,070 Spalding Nov. 15, 1949

